Electronic components can be connected to an antenna. Certain components are configured to exchange information with an external device via the antenna according to a contactless communication protocol. Such components are more simply called, through misuse of language, “contactless components” and can be, for example, so-called “NFC” components, i.e., components compatible with NFC (Near Field Communication) technology. One type of NFC component is an NFC microcontroller.
The acronym NFC (Near Field Communication) refers to a short-distance, high-frequency, wireless communication technology for exchanging data between two contactless devices over a short distance, for example 10 cm.
NFC technology is standardized in documents ISO/IEC 18 092 and ISO/IEC 21 481 but incorporates a variety of pre-existing standards including the Type A and Type B protocols of the ISO/IEC 14 443 standard.
AN NFC microcontroller can be generally used either in “reader” mode or in “card” mode, in order to communicate with another contactless device, for example by using a contactless communication protocol such as the Type A protocol of the ISO/IEC 14 443 standard.
In the “reader” mode, the NFC component acts like a reader with regard to the contactless external device, which can then be a card or a tag. In the reader mode, the NFC component can then read the content of the external device and write information in the external device.
In the “card” mode, the NFC component then behaves like a card or a tag and communicates with the external device which, on this occasion, is a reader.
AN NFC microcontroller can, for example, be incorporated in a cellular mobile phone, and the latter can be used then, in addition to the conventional phone function thereof, to exchange information with the contactless external device.
Many uses are therefore possible, such as getting through transport toll barriers (the mobile phone acts as a transport ticket) or payment uses (the mobile phone acts as a credit card).
Contactless components, such as NFC components, are generally connected to the antenna via an impedance matching circuit with the aim of optimizing radio frequency communication. Furthermore, these external components used in this impedance matching circuit must be extremely well dimensioned, so as to provide maximum performance.